When it is required to transmit a movement from one shaft to another shaft parallel to the first, it is known that generally, gearing is used. When the rotation speed of at least one of the two shafts is very high, the peripheral speed of its gear wheel is reduced by reducing its diameter, but it is then necessary to increase its length to keep its volume constant and consequently to keep its mechanical strength constant. Problems of the loading of the teeth against each other then arise which limit the use of conventional types of gearing.
Likewise, when the power to be transmitted from one shaft to another is high, from about 80 to 100 megawatts, no conventional type of gearing can give a satisfactory result because of the excessive mechanical stresses. Hence, in accordance with the known art, this has led to solutions which comprise a plurality of gear trains. As it is known to manufacture gear wheels which can transmit for example up to 40 or 50 megawatts, circumstances have led to coupling gear trains together in parallel. Divided gear trains have thus been constituted which each bear a load equal to or less than 50 MW and it has become possible to transmit high powers by distributing them among several gear trains each of which is subjected to a power of less than or equal to 50 MW.
It is known at present to manufacture gear transmissions with divided gear trains which have six gears to divide the power to be transmitted by each gear by a factor of two.
If the power P to be transmitted is very high, it is known at present to manufacture a gear transmission with 2 N+2 gears which transmits a power of P/N per gear train. Since each gear wheel requires two bearings, for reasons which will be explained hereinbelow, it is necessary to use 2 N+2 gear wheels and 4 N+4 bearings.
Such an installation occupies a great volume and requires a great number of components. Thus, a known installation which divides the power transmitted by 2, (N=2) requires six gear wheels and twelve bearings. Preferred embodiments of the present invention reduce the number of gear wheels used as well as the number of bearings.